Process for making substituted 2-amino-thiazolones

ABSTRACT

The present invention relates to methods of making compounds that inhibit 11-β-hydroxysteroid dehydrogenase type 1 enzyme (11-β HSD1). One method comprises (a) contacting a compound of formula (II) with a chiral base, deprotonating agent, and an alkylating agent R 3 -LG, (b) contacting the product of (a) with an acid to form a salt, and (c) reacting the salt with a base to form the compound of formula (I); wherein Z, R 1 , R 2 , and R 3  are defined herein.

BACKGROUND OF THE INVENTION

The present invention relates to processes of making compounds thatinhibit 11-β-hydroxysteroid dehydrogenase type 1 enzyme (11-β HSD1).

Hydroxysteroid dehydrogenases (HSDs) regulate the occupancy andactivation of steroid hormone receptors by converting steroid hormonesinto their inactive metabolites. For a recent review, see Nobel et al.,Eur. J. Biochem. 2001, 268:4113-4125.

There exist numerous classes of HSDs. The 11-beta-hydroxysteroiddehydrogenases (11.beta.-HSDs) catalyze the interconversion of activeglucocorticoids (such as cortisol and corticosterone), and their inertforms (such as cortisone and 11-dehydrocorticosterone). The isoform11-beta-hydroxysteroid dehydrogenase type 1 (11.beta.-HSD1) is expressedin liver, adipose tissue, brain, lung and other glucocorticoid tissueand is a potential target for therapy directed at numerous disordersthat may be ameliorated by reduction of glucocorticoid action, such asdiabetes, obesity and age-related cognitive dysfunction. Seckl, et al.,Endocrinology, 2001, 142:1371-1376.

The various isozymes of the 17-beta-hydroxysteroid dehydrogenases(17.beta.-HSDs) bind to androgen receptors or estrogen receptors andcatalyze the interconversion of various sex hormones includingestradiol/estrone and testosterone/androstenedione. To date, sixisozymes have been identified in humans and are expressed in varioushuman tissues including endometrial tissue, breast tissue, colon tissue,and in the testes. 17-beta-Hydroxysteroid dehydrogenase type 2(17.beta.-HSD2) is expressed in human endometrium and its activity hasbeen reported to be linked to cervical cancer. Kitawaki et al., J. Clin.Endocrin. Metab., 2000, 85:1371-3292-3296. 17-beta-Hydroxysteroiddehydrogenase type 3 (17.beta.-HSD3) is expressed in the testes and itsmodulation may be useful for the treatment of androgen-relateddisorders.

Androgens and estrogens are active in their 17.beta.-hydroxyconfigurations, whereas their 17-keto derivatives do not bind toandrogen and estrogen receptors and are thus inactive. The conversionbetween the active and inactive forms (estradiol/estrone andtestosterone/androstenedione) of sex hormones is catalyzed by members ofthe 17.beta.-HSD family. 17.beta.-HSD1 catalyzes the formation ofestradiol in breast tissue, which is important for the growth ofmalignant breast tumors. Labrie et al., Mol. Cell. Endocrinol. 1991,78:C113-C118. A similar role has been suggested for 17.beta.-HSD4 incolon cancer. English et al., J. Clin. Endocrinol. Metab. 1999,84:2080-2085. 17.beta.-HSD3 is almost exclusively expressed in thetestes and converts androstenedione into testosterone. Deficiency ofthis enzyme during fetal development leads to malepseudohermaphroditism. Geissler et al., Nat. Genet. 1994, 7:34-39. Both17.beta.-HSD3 and various 3.alpha.-HSD isozymes are involved in complexmetabolic pathways which lead to androgen shuffles between inactive andactive forms. Penning et al., Biochem. J. 2000, 351:67-77. Thus,modulation of certain HSDs can have potentially beneficial effects inthe treatment of androgen- and estrogen-related disorders.

The 20-alpha-hydroxysteroid dehydrogenases (20.alpha.-HSDs) catalyze theinterconversion of progestins (such as between progesterone and20.alpha.-hydroxy progesterone). Other substrates for 20.alpha.-HSDsinclude 17.alpha.-hydroxypregnenolone or 17.alpha.-hydroxyprogesterone,leading to 20.alpha.-OH steroids. Several 20.alpha.-HSD isoforms havebeen identified and 20.alpha.-HSDs are expressed in various tissues,including the placenta, ovaries, testes and adrenals. Peltoketo, et al.,J. Mol. Endocrinol. 1999, 23:1-11.

The 3-alpha-hydroxysteroid dehydrogenases (3.alpha.-HSDs) catalyze theinterconversion of the androgens dihydrotestosterone (DHT) and5.alpha.-androstane-3.alpha., 17.beta.-diol and the interconversion ofthe androgens DHEA and androstenedione and therefore play an importantrole in androgen metabolism. Ge et al., Biology of Reproduction 1999,60:855-860.

1. Glucorticoids, Diabetes and Hepatic Glucose Production

It has been known for more than half a century that glucocorticoids havea central role in diabetes. For example, the removal of the pituitarygland or the adrenal gland from a diabetic animal alleviates the mostsevere symptoms of diabetes and lowers the concentration of glucose inthe blood (Long, C. D. and Leukins, F. D. W. (1936) J. Exp. Med. 63:465-490; Houssay, B. A. (1942) Endocrinology 30: 884-892). It is alsowell established that glucocorticoids enable the effect of glucagon onthe liver.

The role of 11.beta.HSD1 as an important regulator of localglucocorticoid effect and thus of hepatic glucose production is wellsubstantiated (see, e.g., Jamieson et al. (2000) J. Endocrinol. 165:685-692). Hepatic insulin sensitivity was improved in healthy humanvolunteers treated with the non-specific 11.beta.HSD1 inhibitorcarbenoxolone (Walker, B. R. et al. (1995) J. Clin. Endocrinol. Metab.80: 3155-3159). Furthermore, the expected mechanism has been establishedby different experiments with mice and rats. These studies showed thatthe mRNA levels and activities of two key enzymes in hepatic glucoseproduction were reduced, namely: the rate-limiting enzyme ingluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK), andglucose-6-phosphatase (G6 Pase) the enzyme catalyzing the last commonstep of gluconeogenesis and glycogenolysis. Finally, blood glucoselevels and hepatic glucose production are reduced in mice in which the11.beta.HSD1 gene is knocked-out. Data from this model also confirm thatinhibition of 11.beta.HSD1 will not cause hypoglycemia, as predictedsince the basal levels of PEPCK and G6 Pase are regulated independentlyof glucocorticoids (Kotelevtsev, Y. et al., (1997) Proc. Natl. Acad.Sci. USA 94: 14924-14929).

FR 2,384,498 discloses compounds having a high hypoglycemic effect.Therefore, treatment of hyperglycemia with these compounds may lead tohypoglycemia.

2. Possible Reduction of Obesity and Obesity Related Cardiovascular RiskFactors

Obesity is an important factor in syndrome X as well as in the majority(>80%) of type 2 diabetes, and omental fat appears to be of centralimportance. Abdominal obesity is closely associated with glucoseintolerance, hyperinsulinemia, hypertriglyceridemia, and other factorsof the so-called syndrome X (e.g. increased blood pressure, decreasedlevels of HDL and increased levels of VLDL) (Montague & O'Rahilly,Diabetes 49: 883-888, 2000). Inhibition of the 11.beta.HSD1 enzyme inpre-adipocytes (stromal cells) has been shown to decrease the rate ofdifferentiation into adipocytes. This is predicted to result indiminished expansion (possibly reduction) of the omental fat depot,i.e., reduced central obesity (Bujalska, I. J., S. Kumar, and P. M.Stewart (1997) Lancet 349: 1210-1213).

Inhibition of 11.beta.HSD1 in mature adipocytes is expected to attenuatesecretion of the plasminogen activator inhibitor 1 (PAI-1)—anindependent cardiovascular risk factor (Halleux, C. M. et al. (1999) J.Clin. Endocrinol. Metab. 84: 4097-4105). Furthermore, there is a clearcorrelation between glucocorticoid “activity” and cardiovascular riskfactor suggesting that a reduction of the glucocorticoid effects wouldbe beneficial (Walker, B. R. et al. (1998) Hypertension 31: 891-895;Fraser, R. et al. (1999) Hypertension 33: 1364-1368).

Adrenalectomy attenuates the effect of fasting to increase both foodintake and hypothalamic neuropeptide Y expression. This supports therole of glucocorticoids in promoting food intake and suggests thatinhibition of 11.beta.HSD1 in the brain might increase satiety andtherefore reduce food intake (Woods, S. C. et al. (1998) Science, 280:1378-1383).

3. Possible Beneficial Effect on the Pancreas

Inhibition of 11.beta.HSD1 in isolated murine pancreatic .beta.-cellsimproves glucose-stimulated insulin secretion (Davani, B. et al. (2000)J. Biol. Chem. 2000 Nov. 10; 275(45): 34841-4). Glucocorticoids werepreviously known to reduce pancreatic insulin release in vivo(Billaudel, B. and B. C. J. Sutter (1979) Horm. Metab. Res. 11:555-560). Thus, inhibition of 11.beta.HSD1 is predicted to yield otherbeneficial effects for diabetes treatment, besides the effects on liverand fat.

4. Possible Beneficial Effects on Cognition and Dementia

Stress and glucocorticoids influence cognitive function (de Quervain, D.J. F., B. Roozendaal, and J. L. McGaugh (1998) Nature 394: 787-790). Theenzyme 11.beta.HSD1 controls the level of glucocorticoid action in thebrain and thus contributes to neurotoxicity (Rajan, V., C. R. W.Edwards, and J. R. Seckl, J. (1996) Neuroscience 16: 65-70; Seckl, J.R., Front. (2000) Neuroendocrinol. 18: 49-99). Unpublished resultsindicate significant memory improvement in rats treated with anon-specific 11.beta.HSD1 inhibitor (J. Seckl, personal communication).Based the above and on the known effects of glucocorticoids in thebrain, it may also be suggested that inhibiting 11.beta.HSD1 in thebrain may result in reduced anxiety (Tronche, F. et al. (1999) NatureGenetics 23: 99-103). Thus, taken together, the hypothesis is thatinhibition of 11.beta.HSD1 in the human brain would prevent reactivationof cortisone into cortisol and protect against deleteriousglucocorticoid-mediated effects on neuronal survival and other aspectsof neuronal function, including cognitive impairment, depression, andincreased appetite.

5. Possible Use of Immuno-Modulation Using 11.beta.HSD1 Inhibitors

The general perception is that glucocorticoids suppress the immunesystem. But in fact there is a dynamic interaction between the immunesystem and the HPA (hypothalamo-pituitary-adrenal) axis (Rook, G. A. W.(1999) Baillier's Clin. Endocrinol. Metab. 13: 576-581). The balancebetween the cell-mediated response and humoral responses is modulated byglucocorticoids. A high glucocorticoid activity, such as at a state ofstress, is associated with a humoral response. Thus, inhibition of theenzyme 11.beta.HSD1 has been suggested as a means of shifting theresponse towards a cell-based reaction.

In certain disease states, including tuberculosis, lepra and psoriasisthe immune reaction is normally biased towards a humoral response whenin fact the appropriate response would be cell based. Temporalinhibition of 11.beta.HSD1, local or systemic, might be used to push theimmune system into the appropriate response (Mason, D. (1991) ImmunologyToday 12: 57-60; Rook et al., supra).

An analogous use of 11.beta.HSD1 inhibition, in this case temporal,would be to booster the immune response in association with immunizationto ensure that a cell based response would be obtained, when desired.

6. Reduction of Intraocular Pressure

Recent data suggest that the levels of the glucocorticoid targetreceptors and the 11.beta.HSD enzymes determines the susceptibility toglaucoma (Stokes, J. et al. (2000) Invest. Ophthalmol. 41: 1629-1638).Further, inhibition of 11.beta.HSD1 was recently presented as a novelapproach to lower the intraocular pressure (Walker E. A. et al, posterP3-698 at the Endocrine Society meeting Jun. 12-15, 1999, San Diego).Ingestion of carbenoxolone, a non-specific inhibitor of 11.beta.HSD1,was shown to reduce the intraocular pressure by 20% in normal subjects.In the eye, expression of 11.beta.HSD1 is confined to basal cells of thecorneal epithelium and the non-pigmented epithelialium of the cornea(the site of aqueous production), to ciliary muscle and to the sphincterand dilator muscles of the iris. In contrast, the distant isoenzyme11.beta.HSD2 is highly expressed in the non-pigmented ciliary epitheliumand corneal endothelium. None of the enzymes is found at the trabecularmeshwork, the site of drainage. Thus, 11.beta.HSD1 is suggested to havea role in aqueous production, rather than drainage, but it is presentlyunknown if this is by interfering with activation of the glucocorticoidor the mineralocorticoid receptor, or both.

7. Reduced Osteoporosis

Glucocorticoids have an essential role in skeletal development andfunction but are detrimental in excess. Glucocorticoid-induced bone lossis derived, at least in part, via inhibition of bone formation, whichincludes suppression of osteoblast proliferation and collagen synthesis(Kim, C. H., Cheng, S. L. and Kim, G. S. (1999) J. Endocrinol. 162:371-379). The negative effect on bone nodule formation could be blockedby the non-specific inhibitor carbenoxolone suggesting an important roleof 11.beta.HSD1 in the glucocorticoid effect (Bellows, C. G., Ciaccia,A. and Heersche, J. N. M. (1998) Bone 23: 119-125). Other data suggest arole of 11.beta.HSD1 in providing sufficiently high levels of activeglucocorticoid in osteoclasts, and thus in augmenting bone resorption(Cooper, M. S. et al. (2000) Bone 27: 375-381). Taken together, thesedifferent data suggest that inhibition of 11.beta.HSD1 may havebeneficial effects against osteoporosis by more than one mechanismworking in parallel.

8. Reduction of Hypertension

Bile acids inhibit 11.beta.-hydroxysteroid dehydrogenase type 2. Thisresults in a shift in the overall body balance in favour of cortisolover cortisone, as shown by studying the ratio of the urinarymetabolites (Quattropani, C., Vogt, B., Odermatt, A., Dick, B., Frey, B.M., Frey, F. J. (2001) J Clin Invest. November; 108(9):1299-305.“Reduced activity of 11beta-hydroxysteroid dehydrogenase in patientswith cholestasis”.). Reducing the activity of 11bHSD1 in the liver by aselective inhibitor is predicted to reverse this imbalance, and acutelycounter the symptoms such as hypertension, while awaiting surgicaltreatment removing the biliary obstruction.

WO 99/65884 discloses carbon substituted aminothiazole inhibitors ofcyclin dependent kinases. These compounds may, e.g., be used againstcancer, inflammation and arthritis. U.S. Pat. No. 5,856,347 discloses anantibacterial preparation or bactericide comprising 2-aminothiazolederivative and/or salt thereof. Further, U.S. Pat. No. 5,403,857discloses benzenesulfonamide derivatives having 5-lipoxygenaseinhibitory activity. Additionally, tetrahydrothiazolo[5,4-c]pyridinesare disclosed in: Analgesic tetrahydrothiazolo[5,4-c]pyridines. Fr.Addn. (1969), 18 pp, Addn. to Fr. 1498465. CODEN: FAXXA3; FR 9412319690704 CAN 72:100685 AN 1970:100685 CAPLUS and4,5,6,7-Tetrahydrothiazolo[5,4-c]pyridines. Neth. Appl. (1967), 39 pp.CODEN: NAXXAN NL 6610324 19670124 CAN 68:49593, AN 1968: 49593 CAPLUS.However, none of the above disclosures discloses processes of making thecompounds according to the present invention.

9. Wound Healing

Cortisol performs a broad range of metabolic functions and otherfunctions. The multitude of glucocorticoid action is exemplified inpatients with prolonged increase in plasma glucocorticoids, so called“Cushing's syndrome.” Patients with Cushing's syndrome have prolongedincrease in plasma glucocorticoids and exhibit impaired glucosetolerance, type 2 diabetes, central obesity, and osteoporosis. Thesepatients also have impaired wound healing and brittle skin (Ganong, W.F. Review of Medical Physiology. Eighteenth edition ed. Stamford, Conn.:Appleton & Lange; 1997).

Glucocorticoids have been shown to increase risk of infection and delayhealing of open wounds (Anstead, G. M. Steroids, retinoids, and woundhealing. Adv Wound Care 1998; 11(6):277-85). Patients treated withglucocorticoids have 2-5-fold increased risk of complications whenundergoing surgery (Diethelm, A. G. Surgical management of complicationsof steroid therapy. Ann Surg 1977; 185(3):251-63).

The European patent application No. EP 0902288 discloses a method fordiagnosing the status of wound healing in a patient, comprisingdetecting cortisol levels in said wound. The authors suggest thatelevated levels of cortisol in wound fluid, relative to normal plasmalevels in healthy individuals, correlates with large, non-healing wounds(Hutchinson, T. C., Swaniker, H. P., Wound diagnosis by quantitatingcortisol in wound fluids. European patent application No. EP 0 902 288,published 17 Mar. 1999).

In humans, the 11.beta.-HSD catalyzes the conversion of cortisol tocortisone, and vice versa. The parallel function of 11.beta.-HSD inrodents is the interconversion of corticosterone and11-dehydrocorticosterone (Frey, F. J., Escher, G., Frey, B. M.Pharmacology of 11 beta-hydroxysteroid dehydrogenase. Steroids 1994;59(2):74-9). Two isoenzymes of 11.beta.-HSD, 11.beta.-HSD1 and11.beta.-HSD2, have been characterized, and differ from each other infunction and tissue distribution (Albiston, A. L., Obeyesekere, V. R.,Smith, R. E., Krozowski, Z. S. Cloning and tissue distribution of thehuman 11 beta-hydroxysteroid dehydrogenase type 2 enzyme. Mol CellEndocrinol 1994; 105(2):R11-7). Like GR, 11.beta.-HSD1 is expressed innumerous tissues like liver, adipose tissue, adrenal cortex, gonads,lung, pituitary, brain, eye etc (Monder C, White P C. 11beta-hydroxysteroid dehydrogenase. Vitam Horm 1993; 47:187-271; Stewart,P. M., Krozowski, Z. S. 11 beta-Hydroxysteroid dehydrogenase. Vitam Horm1999; 57:249-324; Stokes, J., Noble, J., Brett, L., Phillips, C., Seckl,J. R., O'Brien, C., et al. Distribution of glucocorticoid andmineralocorticoid receptors and 11beta-hydroxysteroid dehydrogenases inhuman and rat ocular tissues. Invest Ophthalmol V is Sci 2000;41(7):1629-38). The function of 11.beta.-HSD1 is to fine-tune localglucocorticoid action. 11.beta.-HSD activity has been shown in the skinof humans and rodents, in human fibroblasts and in rat skin pouch tissue(Hammami, M. M., Siiteri, P. K. Regulation of 11 beta-hydroxysteroiddehydrogenase activity in human skin fibroblasts: enzymatic modulationof glucocorticoid action. J Clin Endocrinol Metab 1991; 73(2):326-34);Cooper, M. S., Moore, J., Filer, A., Buckley, C. D., Hewison, M.,Stewart, P. M. 11beta-hydroxysteroid dehydrogenase in human fibroblasts:expression and regulation depends on tissue of origin. ENDO 2003Abstracts 2003; Teelucksingh, S., Mackie, A. D., Burt, D., McIntyre, M.A., Brett, L., Edwards, C. R. Potentiation of hydrocortisone activity inskin by glycyrrhetinic acid. Lancet 1990; 335(8697):1060-3; Slight, S.H., Chilakamarri, V. K., Nasr, S., Dhalla, A. K., Ramires, F. J., Sun,Y., et al. Inhibition of tissue repair by spironolactone: role ofmineralocorticoids in fibrous tissue formation. Mol Cell Biochem 1998;189(1-2):47-54).

Wound healing consists of serial events including inflammation,fibroblast proliferation, secretion of ground substances, collagenproduction, angiogenesis, wound contraction and epithelialization. Itcan be divided in three phases; inflammatory, proliferative andremodeling phase (reviewed in Anstead et al., supra).

In surgical patients, treatment with glucocorticoids increases risk ofwound infection and delay healing of open wounds. It has been shown inanimal models that restraint stress slows down cutaneous wound healingand increases susceptibility to bacterial infection during woundhealing. These effects were reversed by treatment with theglucocorticoid receptor antagonist RU486 (Mercado, A. M., Quan, N.,Padgett, D. A., Sheridan, J. F., Marucha, P. T. Restraint stress altersthe expression of interleukin-1 and keratinocyte growth factor at thewound site: an in situ hybridization study. J Neuroimmunol 2002;129(1-2):74-83; Rojas, I. G., Padgett, D. A., Sheridan, J. F., Marucha,P. T. Stress-induced susceptibility to bacterial infection duringcutaneous wound healing. Brain Behav Immun 2002; 16(1):74-84).Glucocorticoids produce these effects by suppressing inflammation,decrease wound strength, inhibit wound contracture and delayepithelialization (Anstead et al., supra). Glucocorticoids influencewound healing by interfering with production or action of cytokines andgrowth factors like IGF, TGF-.beta., EGF, KGF and PDGF (Beer, H. D.,Fassler, R., Werner, S. Glucocorticoid-regulated gene expression duringcutaneous wound repair. Vitam Horm 2000; 59:217-39; Hamon, G. A., Hunt,T. K., Spencer, E. M. In vivo effects of systemic insulin-like growthfactor-I alone and complexed with insulin-like growth factor bindingprotein-3 on corticosteroid suppressed wounds. Growth Regul 1993;3(1):53-6; Laato, M., Heino, J., Kahari, V. M., Niinikoski, J., Gerdin,B. Epidermal growth factor (EGF) prevents methylprednisolone-inducedinhibition of wound healing. J Surg Res 1989; 47(4):354-9; Pierce, G.F., Mustoe, T. A., Lingelbach, J., Masakowski, V. R., Gramates, P.,Deuel, T. F. Transforming growth factor beta reverses theglucocorticoid-induced wound-healing deficit in rats: possibleregulation in macrophages by platelet-derived growth factor. Proc NatlAcad Sci USA 1989; 86(7):2229-33). It has also been shown thatglucocorticoids decrease collagen synthesis in rat and mouse skin invivo and in rat and human fibroblasts (Oishi, Y., Fu, Z. W., Ohnuki, Y.,Kato, H., Noguchi, T. Molecular basis of the alteration in skin collagenmetabolism in response to in vivo dexamethasone treatment: effects onthe synthesis of collagen type I and III, collagenase, and tissueinhibitors of metalloproteinases. Br J Dermatol 2002; 147(5):859-68).

U.S. Patent Application Publication No. 2006/0142357 and WO 2005/116002describe 11-β-HSD1 inhibitors of the following general structure andcertain processes for making the same:

It is evident that this type of 11-β-HSD1 inhibitors is of greatimportance from a medicinal point of view. There is, therefore, a needfor an efficient process to synthesize these compounds, particularly theoptical isomers thereof in high purity, for large scale preparationsuitable for commercial production.

SUMMARY OF THE INVENTION

The present invention provides in one embodiment a process for thepreparation of compounds having formula I, or a tautomer, stereoisomer,geometric isomer, optical isomer, hydrate, solvate, prodrug, orpharmaceutically acceptable salt thereof:

Variable Z is S or O.

R¹ is selected from C₁₋₈ alkyl, C₂₋₈ alkenyl, C₃₋₁₀-cycloalkyl,C₃₋₁₀-cycloalkenyl, C₃₋₁₀-cycloalkenyl-C₁₋₈-alkyl, aryl,aryl-C₁₋₈-alkyl, heterocyclyl, heterocyclyl-C₁₋₄-alkyl and haloalkyl. Inthe definition of R¹, any aryl, cycloalkyl, or heterocyclyl residue isoptionally independently substituted by one or more C₁₋₈-alkyl, aryl,halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl, R⁴R⁵N—C₁-C₈-alkyl,C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl or C₁-C₈-alkyl-sulfonyl.

R² and R³ are independently selected from C₁₋₈-alkyl, C₁₋₄-alkoxy,C₃₋₁₀-cycloalkyl, heterocyclyl, C₃₋₁₀-cycloalkyl-C₁₋₈-alkyl,CN—C₁₋₈-alkyl, aryl, aryl-C₁₋₈-alkyl, heterocyclyl-C₁₋₈-alkyl andhaloalkyl. In the definitions for R² and R³, any aryl, cycloalkyl, orheterocyclyl residue is optionally independently substituted by one ormore C₁₋₈-alkyl, aryl, halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl,R⁴R⁵N—C₁-C₈-alkyl, C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl orC₁-C₈-alkyl-sulfonyl.

R⁴ and R⁵ are each independently selected from hydrogen, C₁-C₈ alkyl,C₁-C₈ alkoxy, —NR⁶R⁶, —S—(C₁-C₈)alkyl, aryl and heterocyclyl. In thedefinitions for R⁴ and R⁵, any alkyl, alkoxy, heterocyclyl or aryl maybe substituted with one to three substituents selected from -halo,unsubstituted C₁-C₈ alkyl, unsubstituted C₁-C₈ alkoxy, unsubstitutedC₁-C₈ thioalkoxy and unsubstituted aryl(C₁-C₄)alkyl.

R⁶ is independently selected from hydrogen, C₁-C₈ alkyl, aryl-C₁-C₈alkyl, C₁-C₈ alkoxy, —S—(C₁-C₈)alkyl, heterocyclyl and aryl. In thedefinition for R⁶, any alkyl, heterocyclyl or aryl may be substitutedwith one to three substituents selected from -halo, unsubstituted C₁-C₈alkyl, unsubstituted C₁-C₈ alkoxy, unsubstituted C₁-C₈ thioalkoxy andunsubstituted aryl(C₁-C₄)alkyl.

The process comprises the following steps:

(a) contacting a compound of formula II with (i) a chiral base in thepresence of an amine, and an alkylating agent R₃-LG; wherein LG is aleaving group;

(b) contacting the product of (a) with an acid HB to form a salt offormula I′ wherein B is an organic or inorganic anion; and

(c) reacting the salt of formula I′ with a base to yield the compound offormula I.

In another embodiment, the invention provides another process for thepreparation of a compound having formula I, or a tautomer, stereoisomer,geometric isomer, optical isomer, hydrate, solvate, prodrug, orpharmaceutically acceptable salt thereof:

The process comprises contacting a compound of formula II

with a chiral base in the presence of a deprotonating reagent andalkylating agent R³-LG. Z is S or O.

R¹ is selected from C₁₋₈ alkyl, C₂₋₈ alkenyl, C₃₋₁₀-cycloalkyl,C₃₋₁₀-cycloalkenyl, C₃₋₁₀-cycloalkyl-C₁₋₈-alkyl,C₃₋₁₀-cycloalkenyl-C₁₋₈-alkyl, aryl, aryl-C₁₋₈-alkyl, heterocyclyl,heterocyclyl-C₁₋₈-alkyl and haloalkyl; wherein any aryl, cycloalkyl, orheterocyclyl residue is optionally independently substituted by one ormore C₁₋₈-alkyl, aryl, halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl,R⁴R⁵N—C₁-C₈-alkyl, C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl orC₁-C₈-alkyl-sulfonyl.

R² and R³ are independently selected from C₁₋₈-alkyl, C₁₋₈-alkoxy,C₃₋₁₀-cycloalkyl, heterocyclyl, C₃₋₁₀-cycloalkyl-C₁₋₈-alkyl,CN—C₁₋₈-alkyl, aryl, aryl-C₁₋₈-alkyl, heterocyclyl-C₁₋₈-alkyl andhaloalkyl; wherein any aryl, cycloalkyl, or heterocyclyl residue isoptionally independently substituted by one or more C₁₋₈-alkyl, aryl,halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl, R⁴R⁵N—C₁-C₈-alkyl,C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl or C₁-C₈-alkyl-sulfonyl.

R⁴ and R⁵ are each independently selected from hydrogen, C₁-C₈ alkyl,C₁-C₈ alkoxy, —NR⁶R⁶, —S—(C₁-C₈)alkyl, aryl and heterocyclyl; where inthe definition of R⁴ and R⁵ any alkyl, alkoxy, heterocyclyl or aryl maybe substituted with one to three substituents selected from -halo,unsubstituted C₁-C₈ alkyl, unsubstituted C₁-C₈ alkoxy, unsubstitutedC₁-C₈ thioalkoxy and unsubstituted aryl(C₁-C₄)alkyl.

R⁶ is independently selected from hydrogen, C₁-C₈ alkyl, aryl-C₁-C₈alkyl, C₁-C₈ alkoxy, —S—(C₁-C₈)alkyl, heterocyclyl and aryl; where inthe definition of R⁶ any alkyl, heterocyclyl or aryl may be substitutedwith one to three substituents selected from -halo, unsubstituted C₁-C₈alkyl, unsubstituted C₁-C₈ alkoxy, unsubstituted C₁-C₈ thioalkoxy andunsubstituted aryl(C₁-C₄)alkyl.

LG is a leaving group.

Another embodiment of the invention is a process for preparing acompound of formula III:

In one embodiment, the process comprises the following steps:

(a) contacting a compound of formula IV

with a chiral base of the formula

in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA), and

(b) reacting the product of step (a) with isopropyl iodide.

In one embodiment, the process further comprises the following steps:

(c) contacting the product of step (b) with MeSO₃H to form a mesylatesalt, and

(d) reacting the mesylate salt from step (c) with NaOH to yield thecompound of formula III.

In still another embodiment, the process further comprises the step ofisolating the mesylate salt after step (c) and before step (d).

Another embodiment of the invention is a process for the preparation ofa compound according to formula V:

The process comprises

(a) contacting a compound of formula (VI)

with a chiral base of the formula

in the presence of TMEDA; and

(b) reacting the product of step (a) with n-propyl iodide.

DETAILED DESCRIPTION

The various terms used, separately and in combinations, in the processesherein described are defined below.

The expression “comprising” means “including but not limited to.” Thus,other non-mentioned substances, additives, carriers, or steps may bepresent.

The term “aryl” in the present description is intended to includearomatic rings (monocyclic or bicyclic) having from 6 to 10 ring carbonatoms, such as phenyl (Ph), naphthyl, and indanyl (i.e.,2,3-dihydroindenyl). An aryl group may be substituted by C₁₋₆-alkyl.Examples of substituted aryl groups are benzyl, and 2-methylphenyl.

The term “heteroaryl” is a monocyclic, bi- or tricyclic aromatic ringsystem (only one ring need to be aromatic) having from 5 to 14 ringatoms (mono- or bicyclic), in which one or more of the ring atoms areother than carbon, such as nitrogen, sulfur, oxygen and selenium as partof the ring system. In some embodiments, the ring has from 5 to 10 ringatoms such as 5, 6, 7, 8, 9 or 10. Examples of such heteroaryl rings arepyrrole, imidazole, thiophene, furan, thiazole, isothiazole,thiadiazole, oxazole, isoxazole, oxadiazole, pyridine, pyrazine,pyrimidine, pyridazine, pyrazole, triazole, tetrazole, chroman,isochroman, quinoline, quinoxaline, isoquinoline, phthalazine,cinnoline, quinazoline, indole, isoindole, benzothiophene, benzofuran,isobenzofuran, benzoxazole, 2,1,3-benzoxadiazole, benzopyrazole;benzothiazole, 2,1,3-benzothiazole, 2,1,3-benzoselenadiazole,benzimidazole, indazole, benzodioxane, indane, 1,5-naphthyridine,1,8-naphthyridine, acridine, fenazine and xanthene.

The term “heterocyclic” and “heterocyclyl” relates to unsaturated aswell as partially and fully saturated mono-, bi- and tricyclic ringshaving from 4 to 14 ring atoms having one or more heteroatoms (e.g.,oxygen, sulfur, or nitrogen) as part of the ring system and the reminderbeing carbon, such as, for example, the heteroaryl groups mentionedabove as well as the corresponding partially saturated or fullysaturated heterocyclic rings. Exemplary saturated heterocyclic rings areazetidine, pyrrolidine, piperidine, piperazine, morpholine,thiomorpholine, 1,4-oxazepane, azepane, phthalimide, indoline,isoindoline, 1,2,3,4-tetrahydroquinoline,1,2,3,4-tetrahydroisoquinoline, 3,4-dihydro-2H-1,4-benzoxazine,hexahydroazepine, 3,4-dihydro-2(1H)isoquinoline, 2,3-dihydro-1H-indole,1,3-dihydro-2H-isoindole, azocane, 1-oxa-4-azaspiro[4.5]dec-4-ene,decahydroisoquinoline, and 1,4-diazepane. In addition, the heterocyclylor heterocyclic moiety may optionally be substituted with one or moreoxo groups.

C₁₋₈-alkyl is a straight or branched alkyl group containing 1-8 carbonatoms. Exemplary alkyl groups include methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl,isohexyl, n-heptyl, and n-octyl. For parts of the range “C₁₋₈-alkyl” allsubgroups thereof are contemplated such as C₁₋₇-alkyl, C₁₋₆-alkyl,C₁₋₅-alkyl, C₁₋₄-alkyl, C₂₋₈-alkyl, C₂₋₇-alkyl, C₃₋₇-alkyl, C₄₋₆-alkyl,etc.

C₁₋₈-alkoxy is a straight or branched alkoxy group containing 1-8 carbonatoms. Exemplary alkoxy groups include methoxy, ethoxy, propoxy,isopropoxy, butoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy,hexyloxy, isohexyloxy, n-heptyloxy, and n-octyloxy. For parts of therange “C₁₋₆-alkoxy” all subgroups thereof are contemplated such asC₁₋₇-alkoxy, C₁₋₆-alkoxy, C₁₋₅-alkoxy, C₁₋₄-alkoxy, C₂₋₈-alkoxy,C₂₋₇-alkoxy, C₂₋₆-alkoxy, C₂₋₅-alkoxy, C₃₋₇-alkoxy, C₄₋₆-alkoxy, etc.

C₂₋₈-alkenyl is a straight or branched alkenyl group containing 2-8carbon atoms. Exemplary alkenyl groups include vinyl, 1-propenyl,2-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl,1-hexenyl, 2-hexenyl, 1-heptenyl, and 1-octenyl. For parts of the range“C₂₋₈-alkenyl” all subgroups thereof are contemplated such asC₂₋₇-alkenyl, C₂₋₆-alkenyl, C₂₋₅-alkenyl, C₂₋₄-alkenyl, C₃₋₈-alkenyl,C₃₋₇-alkenyl, C₃₋₆-alkenyl, C₃₋₅-alkenyl, C₄₋₇-alkenyl, C₅₋₆-alkenyl,etc.

C₃₋₁₀-cycloalkyl is an optionally substituted monocyclic, bicyclic ortricyclic alkyl group containing between 3-10 carbon atoms. Exemplarycycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,bicyclo[2.2.1]hept-2-yl, tricyclo[3.3.1.0˜3,7˜]non-3-yl,(1R,2R,3R,5S)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl,(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl, 1-adamantyl,noradamantyl, and 2,2,3,3-tetramethylcyclopropyl. For parts of the range“C₃₋₁₀-cycloalkyl” all subgroups thereof are contemplated such asC₃₋₉-cycloalkyl, C₃₋₈-cycloalkyl, C₃₋₇-cycloalkyl, C₃₋₆-cycloalkyl,C₃₋₅-cycloalkyl, C₄₋₁₀-cycloalkyl, C₅₋₁₀-cycloalkyl, C₆₋₁₀-cycloalkyl,C₇₋₁₀-cycloalkyl, C₈₋₉-cycloalkyl, etc. In addition, the cycloalkylmoiety can be substituted with one or more oxo groups.

C₃₋₁₀-cycloalkenyl is an optionally alkyl substituted cyclic, bicyclicor tricyclic alkenyl group containing totally 3-10 carbon atoms.Exemplary cycloalkenyl groups include cyclopropenyl, cyclobutenyl,cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclononenyl,cyclodecenyl, and bicyclo[2.2.1]hept-5-en-2-yl. For parts of the range“C₃₋₁₀-cycloalkenyl” all subgroups thereof are contemplated such asC₃₋₉-cycloalkenyl, C₃₋₈-cycloalkenyl, C₃₋₇-cycloalkenyl,C₃₋₆-cycloalkenyl, C₃₋₅-cycloalkenyl, C₄₋₁₀-cycloalkenyl,C₅₋₁₀-cycloalkenyl, C₆₋₁₀-cycloalkenyl, C₇₋₁₀-cycloalkenyl,C₈₋₉-cycloalkenyl, etc. In addition, the cycloalkenyl moiety mayoptionally be substituted with one or more oxo groups.

The terms “halogen” and “halo” in the present description is intended toinclude fluorine, chlorine, bromine and iodine.

The term “-hetero(C₁-C₈)alkyl” refers to a moiety wherein a hetero atom,selected from optionally substituted nitrogen, sulfur and oxygen, is thepoint of attachment to the core molecule and is attached to a C₁-C₈alkyl chain.

Combinations of substituents and variables envisioned by this inventionare only those that result in the formation of stable compounds. Theterm “stable”, as used herein, refers to compounds which possessstability sufficient to allow manufacture and which maintains theintegrity of the compound for a sufficient period of time to be usefulfor the purposes detailed herein (e.g., therapeutic administration to asubject for the treatment of disease, 11-.beta.-HSD1 inhibition,11-.beta.-HSD1-mediated disease).

As used herein, the term “prodrug” means a derivative of a compound thatcan hydrolyze, oxidize, or otherwise react under biological conditions(in vitro or in vivo) to provide an active compound Examples of prodrugsinclude, but are not limited to, derivatives and metabolites of acompound derivative that include biohydrolyzable groups such asbiohydrolyzable amides, biohydrolyzable esters, biohydrolyzablecarbamates, biohydrolyzable carbonates, biohydrolyzable ureides, andbiohydrolyzable phosphate analogues (e.g., monophosphate, diphosphate ortriphosphate). Preferably, prodrugs of compounds with carboxylfunctional groups are the lower alkyl esters of the carboxylic acid. Thecarboxylate esters are conveniently formed by esterifying any of thecarboxylic acid moieties present on the molecule. Prodrugs can typicallybe prepared using well-known methods, such as those described byBurger's Medicinal Chemistry and Drug Discovery 6^(th) ed. (Donald J.Abraham ed., 2001, Wiley) and Design and Application of Prodrugs (H.Bundgaard ed., 1985, Harwood Academic Publishers Gila).

A “tautomer” is one of two or more structural isomers that exist inequilibrium and is readily converted from one isomeric form to another.In the present case, tautomers of the structures below are encompassedby the present invention.

As used herein, “hydrate” is a form of a compound wherein watermolecules are combined in a certain ratio as an integral part of thecrystal structure of the compound.

As used herein, “solvate” is a form of a compound where solventmolecules are combined in a certain ratio as an integral part of thecrystal structure of the compound.

As used herein, the term “geometrical isomers” refers compounds thathave the same molecular formula but the atoms are in differentnon-equivalent positions relative to one another.

As used herein, the term “optical isomers” refers to compounds withchiral atoms which have the ability to rotate plane polarized light, andare typically designated using the conventional R/S configuration. Theterm “optical isomer” includes enantiomers and diastereomers as well ascompounds which can be distinguished one from the other by thedesignations of (D) and (L).

“Pharmaceutically acceptable” means in the present description beinguseful in preparing a pharmaceutical composition that is generally safe,non-toxic and neither biologically nor otherwise undesirable andincludes being useful for veterinary use as well as human pharmaceuticaluse.

“Pharmaceutically acceptable salts” mean salts which arepharmaceutically acceptable, as defined above, and which possess thedesired pharmacological activity. Such salts include acid addition saltsformed with organic and inorganic acids, such as hydrogen chloride,hydrogen bromide, hydrogen iodide, sulfuric acid, phosphoric acid,acetic acid, glycolic acid, maleic acid, malonic acid, oxalic acid,methanesulfonic acid, trifluoroacetic acid, fumaric acid, succinic acid,tartaric acid, citric acid, benzoic acid, ascorbic acid and the like.Base addition salts may be formed with organic and inorganic bases, suchas sodium, ammonia, potassium, calcium, ethanolamine, diethanolamine,N-methylglucamine, choline and the like. Included in the invention arepharmaceutically acceptable salts or compounds of any of the formulaeherein.

Depending on its structure, the phrase “pharmaceutically acceptablesalt,” as used herein, refers to a pharmaceutically acceptable organicor inorganic acid or base salt of a compound. Representativepharmaceutically acceptable salts include, e.g., alkali metal salts,alkali earth salts, ammonium salts, water-soluble and water-insolublesalts, such as the acetate, amsonate(4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzonate,bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium,calcium edetate, camsylate, carbonate, chloride, citrate, clavulariate,dihydrochloride, edetate, edisylate, estolate, esylate, fiunarate,gluceptate, gluconate, glutamate, glycollylarsanilate,hexafluorophosphate, hexylresorcinate, hydrabamine, hydrobromide,hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate,lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate,N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate,oxalate, palmitate, pamoate (1,1-methene-bis-2-hydroxy-3-naphthoate,einbonate), pantothenate, phosphate/diphosphate, picrate,polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate,subacetate, succinate, sulfate, sulfosaliculate, suramate, tannate,tartrate, teoclate, tosylate, triethiodide, and valerate salts.Furthermore, a pharmaceutically acceptable salt can have more than onecharged atom in its structure. In this instance the pharmaceuticallyacceptable salt can have multiple counterions. Hence, a pharmaceuticallyacceptable salt can have one or more charged atoms and/or one or morecounterions.

The following abbreviations are used throughout the description andappended claims, and they have the following meanings:

“TMEDA” means N,N,N′N′-tetramethylethylenediamine.

“TMPDA” means N,N,N′N′-tetramethylpropylenediamine.

“TMBDA” means N,N,N′N′-tetramethylbutylenediamine.

“Ar” means aryl.

“Ph” means phenyl.

“de” means diastereomeric excess.

“MTBE” means methyl tertiary-butyl ether.

“IPA” means isopropyl alcohol.

“DCM” means dichloromethane.

“MSA” means methane sulfonic acid (MeSO₃H).

“Tint” means the internal temperature of the reaction mixture.

“LCAP” means Peak Area % by HPLC

“TGA” means Thermogravimetric Analysis

The chemicals used in the synthetic routes delineated herein include,for example, solvents, reagents, and catalysts. The methods describedabove may also additionally include steps, either before or after thesteps described specifically herein, to add or remove suitableprotecting groups in order to ultimately allow synthesis of thecompounds. In addition, various synthetic steps may be performed in analternate sequence or order to give the desired compounds. Syntheticchemistry transformations and protecting group methodologies (protectionand deprotection) useful in synthesizing applicable compounds are knownin the art and include, for example, those described in R. Larock,Comprehensive Organic Transformations, VCH Publishers (1989); T. W.Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3^(rd)Ed., John Wiley and Sons (1999); L. Fieser and M. Fieser, Fieser andFieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); andL. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, JohnWiley and Sons (1995) and subsequent editions thereof.

Some embodiments of the present invention contemplate processes ofmaking a compound of the general formula I, as described above, viaasymmetric alkylation of a compound of formula II:

The compound of formula (II) is prepared by the following generalsynthetic method:

If the appropriate urea, thiourea, or alpha-bromocarboxylic acid orester is not commercially available, the appropriate starting materialcan be prepared in accordance with the methods described in U.S. PatentApplication Publication No. 2006/0142357.

In one embodiment, Z is S, referring to thiazolinones. Variable Z alsocan be O, referring to oxazolinones.

In another embodiment, R₁ is selected from the group consisting of

An exemplary value for R¹ is:

In one embodiment, R₂ and R₃ are independently selected from methyl,isopropyl, and n-propyl.

In another embodiment, the chiral base is selected from the followinggroup of bases:

In another embodiment, the chiral base is selected from

wherein:

X is selected from O, N, S, and C₁₋₈-alkylene;

Y is selected from C₁₋₈-alkyl, aryl, and heterocyclyl; and

M is selected from Li, Na, K, Cs, Cu, Zn, and Mg; and

Ar is aryl.

In another embodiment, the chiral base is

In some embodiments, the chiral base is selected from the groupconsisting of:

wherein M is as defined hereinabove.

In some embodiments, the chiral base is an ephedrine salt, i.e.:

wherein M is as defined hereinabove. Thus, in one embodiment, the chiralbase is a salt of (1R,2S)-(−)-ephedrine:

In another embodiment, the chiral base is a salt of(1S,2R)-(−)-ephedrine:

An example of “M” in all of these embodiments is lithium ion.

In another embodiment, the leaving group LG in R³LG is selected from thegroup consisting of Cl, Br, I, —OS(O)₂CH₃, —OS(O)₂C₄F₉, —OS(O)₂CF₃, and—OS(O)₂(4-CH₃-phenyl).

In another embodiment, the amine is selected from triethylamine,trimethylamine, triisopropyl amine, N,N,N′N′-tetramethylethylenediamine(TMEDA), N,N,N′N′-tetramethylpropylenediamine (TMPDA), andN,N,N′N′-tetramethylbutylenediamine (TMBDA). An exemplary amine in thisregard is TMEDA.

In another embodiment, the solvent used in step (a) is selected from thegroup consisting of benzene, toluene, trifluorotoluene, xylene,chlorobenzene, dialkyl ethers, THF, dioxane, DMF, halogenatedhydrocarbon solvents, ester solvents, and mixtures thereof. An exemplarysolvent in this regard is toluene.

In one embodiment, the compound of Formula II is contacted with thechiral base first, followed by the alkylating agent R³-LG. In anotherembodiment, the compound of Formula II is contacted first with thealkylating agent R³-LG, followed by the chiral base.

In one embodiment, the acid in step (b) is selected from the consistingof HCl, H₂SO₄, CH₃C(O)OH, CF₃C(O)OH, MeSO₃H, and C₆H₅SO₃H.

In another embodiment, the acid in step (b) is MeSO₃H.

In one embodiment, the base in step (c) is selected from the groupconsisting of LiOH, NaOH, KOH, and sodium acetate.

In another embodiment, the base in step (c) is NaOH.

In one embodiment, the diastereomeric excess (de) value of the productis at least 85%, 90%, 95%, or 98%.

In view of the foregoing considerations, and the specific examplesbelow, those who are skilled in the art will appreciate that a givenselection of chiral base, amine, solvent, acid, or base can determinethe chirality of the end product, and/or the de thereof. Making such aselection is well within the ambit of the skilled artisan.

Another embodiment of the present invention is a process for thepreparation of a compound of formula III

from a compound of formula IV

as described generally above.

In this embodiment, the process comprises the steps of (a) contactingcompound IV with a chiral base of the following formula

in the presence of TMEDA, and then (b) reacting the product from step(a) with isopropyl iodide.

In one embodiment, the process further comprises the steps of (c)contacting the product of step (b) with MeSO₃H to form a mesylate salt;and (d) reacting the mesylate salt from step (c) with NaOH to yield thecompound of formula III.

In one embodiment, the product of step (b) is of de value at least 90%,95%, or 98%.

In another embodiment, the product of step (d) is of de value at least99%.

Still another embodiment of the invention is a further process for thepreparation of a compound according to formula III:

In this embodiment, the process comprises (a) contacting a compound offormula (IV)

with a chiral base in the presence of a deprotonating reagent; and (b)reacting the product of step (a) with isopropyl iodide. The term “chiralbase” as used hereinthroughout contemplates a chiral molecule that is abase. The term “chiral base” additionally contemplates a chiral basethat results from deprotonation of a neutral or free base. Hence, achiral base containing the ion “M” as defined hereinabove formallyrefers to a salt of the free base. A free base features —OH and —NH or—NH₂ groups, for instance, meaning chiral bases that are notdeprotonated.

Illustrative examples of a chiral base include the following:

In some embodiments, the chiral base is

In the embodiment described above, the process can be carried out in thepresence of a deprotonating agent. Many deprotonating agents arewell-known to those who are skilled in the field of organic synthesis.For instance, deprotonating agents include but are not limited tometalorganics, such as alkyllithiums. Common examples of alkyllithiumsare methyllithium, n-butyllithium, tert-butyllithium, and hexyllithium.Other deprotonating reagents include metal hydrides, such as, forinstance, lithium hydride, sodium hydride, and potassium hydride.

The invention will now be described in reference to the followingExamples. These examples are not to be regarded as limiting the scope ofthe present invention, but shall only serve in an illustrative manner.

EXAMPLES Example 1 Preparation of(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-methyl-5-propylthiazol-4(5H)-one(6)

Materials MW Amount mMol Eq Other 5-Methylthiazolinone (1) 224.32 25.25g 112.56 1 n/a Chiral amine (2) 448.64 110.2 g 245.6 2 n/a n-BuLi (3) —181 mL 488.7 4 2.7M toluene TMEDA (4) 116.21 37 mL 245.2 2 d = 0.775g/mL n-PrI (5) 169.99 88 mL 900.48 8 d = 1.742 g/mL Toluene — 160 + 375mL — — —

5-Methylthiazolinone (1) (25.25 g) was suspended in 500 mL of anhydroustoluene. The solvent of this slurry was distilled at 44° C. and 50 mbarreduced pressure to a total volume of 160 mL. To a jacketed 3 L reactor,equipped with a Julabo LH-50 process chiller, N₂ line, thermocouple, andoverhead stirrer, was charged 110.2 g of chiral amine (2) solid. Thereactor and contents were flushed with N₂. Toluene (375 mL) was chargedto the purged reactor via cannula, yielding a clear solution of chiralamine (2). This solution was cooled to −15° C. Butyllithium (3) (181 mL,2.7 M in toluene) was transferred via cannula to a 250 mL additionfunnel attached to the reactor. The butyllithium (3) was added dropwiseover a period of 30 minutes, with the internal temperature (“Tint”)never rising above −9.0° C.

TMEDA (4) (37 mL) was charged to the reactor via syringe after Tint hadbeen re-established at −15.5° C. After a 30 minute aging, the 160 mLslurry of 5-methylthiazolinone (1) in toluene was charged portion-wisevia cannula, with the Tint never rising above −4.5° C. The Tint was thenadjusted to 16° C. and the reaction was held for 1 hour. After thisaging period, the Tint was readjusted to −15.5° C. N-propyl iodide (5)(88 mL) was charged via cannula over a period of 15 minutes, maintaininga Tint below −12° C. The Tint stabilized at −14.5° C. after completionof nPrI addition, and the mixture was stirred out for 16 hours.

After 16 hours, HPLC analysis indicated less than 5% residual startingmaterial and a de of 34%. The reactor was equipped with a 250 mLaddition funnel, to which was added 250 mL sat NH₄Cl. A fast dropwiseaddition of NH₄Cl was established and the saturated solution was addedover a period of 1.5 hours, during which time the Tint never rose above−8.0° C. After completion of the quench, the reactor contents werewarmed to 22° C., and the mixture was agitated. The stirring was thenhalted and the layers were allowed to separate for 5 minutes, afterwhich the bottom aqueous component was drained off. A second 250 mL sat.NH₄Cl quench was performed in the manner previously mentioned. Thetoluene layer was then acidified with 3×200 mL 2N AcOH and theextraction performed by agitation, phase separation, and draining of thebottom aqueous layer. A final extraction was performed with 200 mL ofsat. NaHCO₃ by the method previously outlined. The toluene layer postworkup was then polish filtered, yielding 800 mL of a clear solution.

The total volume of the 800 mL toluene solution was reduced to 100 mL byremoving the toluene under reduced pressure (40° C., 60 mbar, rotaryevaporator). This concentrated toluene solution was transferred to a 3neck 1 L round bottom flask, followed by a 10 mL toluene wash. Afterheating the mixture to 60° C., heptane (400 mL) was added via a ILaddition funnel over a period of 35 minutes. After completion of heptaneaddition the homogeneous solution was slowly cooled to 22° C. over 2hours, resulting in a fine slurry. An additional 1 L of heptane wascharged to the slurry, and the mixture was allowed to stir at 22° C. for48 hours. After this time the slurry was filtered on a medium porosity300 mL sinter funnel, washed with 50 mL of 0° C. heptane, and driedusing house vacuum accompanied with an N₂ sweep for 16 hours. After thisdrying period the weight of the recovered solids was 20.3 g (67.7yield), with an LCAP of >98% and a de=27%. ¹H NMR [(CD₃)₂SO] δ: 9.00 (d,1H), 3.75 (m, 1H), 2.24 (m, 1H), 2.20 (m, 1H), 1.68 (m, 3H), 1.47 (compm, 8H), 1.12 (m, 4H), and 0.84 ppm (m, 3H).

Example 2 Preparation of(5S)-2-(bicyclo[2.2.1]hept-5-en-2-ylamino)-5-methyl-5-propylthiazol-4(5H)-one(8)

Materials MW Amount mMol Eq Other 5-Methylthiazolinone (7) 222.31 25.0 g112.56 1 n/a Chiral amine (2) 448.64 110.2 g 245.6 2 n/a n-BuLi (3) —181 mL 488.7 4 2.7M toluene TMEDA (4) 116.21 37 mL 245.2 2 d = 0.775g/mL n-PrI (5) 169.99 88 mL 900.48 8 d = 1.742 g/mL Toluene — 160 + 375mL — — —

Procedure:

5-Methylthiazolinone (7) (25.0 g) was suspended in 480 mL of anhydroustoluene. The solvent of this slurry was distilled at 44° C. and 50 mbarreduced pressure to a total volume of 160 mL. To jacketed 3 L reactor,equipped with a Julabo LH-50 process chiller, N₂ line, thermocouple, andoverhead stirrer, was charged 110.2 g of chiral amine (2) solid. Thereactor and contents were flushed with N₂. Toluene (375 mL) was chargedto the purged reactor via cannula, yielding a clear solution of chiralamine (2). This solution was cooled to −15° C. Butyllithium (3) (181 mL,2.7 M in toluene) was transferred via cannula to a 250 mL additionfunnel attached to the reactor. The butyllithium was added dropwise overa period of 45 minutes, with the Tint never rising above −8.0° C. TMEDA(4) (37 mL) was charged to the reactor via syringe after the Tint hadbeen re-established at −15.5° C. After a 20 minute aging, the 160 mLslurry of thiazalinone (7) in toluene was charged portionwise viacannula, with the Tint never rising above −13° C. The Tint was thenadjusted to 16° C. and the reaction was held for 30 minutes. After thisaging period, the Tint was readjusted to −15.5° C. N-propyl iodide (5)(88 mL) was charged via cannula over a period of 20 minutes, maintaininga Tint below −12° C. The Tint stabilized at −14.5° C. after completionof nPrI addition, and was stirred out for 16 hours.

After 16 hours HPLC analysis indicated less than 1% residual startingmaterial and a de of 41%. The reactor was equipped with a 250 mLaddition funnel, to which was added 250 mL sat NH₄Cl. A fast dropwiseaddition of NH₄Cl was established and the saturated solution was addedover a period of 1.5 hours, during which time the Tint never rose above−8.0° C. After completion of the quench, the reactor contents werewarmed to 22° C., and the mixture was agitated. The stirring was thenhalted and the layers were allowed to separate for 5 minutes, afterwhich the bottom aqueous component was drained off. A second 250 mL sat.NH₄Cl quench was performed in the manner previously mentioned. Thetoluene layer was then acidified with 3×200 mL 2N AcOH and theextraction performed by agitation, phase separation, and draining of thebottom aqueous layer. A final extraction was performed with 200 mL ofsat. NaHCO₃ by the method previously outlined. The toluene layer postworkup was then polish filtered, yielding 775 mL of a clear solution.

The clear toluene solution was concentrated to 100 mL at 50 C and 60mbar, after which anhydrous octane (400 mL) was charged to the flask.This mixture was concentrated at 60° C. and 80 mbar to ˜100 mL totalvolume, and was then diluted to 400 mL with octane. This solution wasslowly cooled to 22° C., yielding a slurry that was stirred for 2 hours.The slurry was filtered on a medium porosity sinter funnel and driedunder house vacuum overnight with an N₂ sweep, yielding 11.3 g ofsolids. The 350 mL of remaining mother liquor was concentrated down to50 mL total volume (60° C., 70 mbar) and upon cooling to 22° C. a whitesolid rapidly crashed out. This solid was filtered in the same manner ofthe first batch, yielding 9.9 g of a white solid. Combination of bothprecipitates afforded 21.2 g (71.1% yield) of solids, 90% LCAP, de=43%.¹H NMR [(CD₃)₂SO] δ: 9.26 (d, 1H), 6.21 (m, 1H), 6.09 (m, 1H), 3.75 (m,1H), 2.86 (m, 1H), 2.78 (d, 1H), 1.54 (comp m, 10H), 1.04 (m, 1H), and0.86 ppm (m, 3H). Note: a minor isomer was also visible by ¹H NMR.

Example 3 Preparation of(S)-5-isopropyl-5-methyl-2-((S)-1-phenylethylamino)thiazol-4(5H)-one(11)

Materials MW Amount mMol Eq Other 5-Methylthiazolinone (9) 233.31 26.3 g112.56 1 96.9% de Chiral amine (2) 448.64 110.2 g 245.6 2 n/a n-BuLi (3)— 181 mL 488.7 4 2.7M toluene TMEDA (4) 116.21 37 mL 245.2 2 d = 0.775g/mL i-PrI (10) 169.99 90 mL 900.48 8 d = 1.70  g/mL Toluene — 160 + 375mL — — —

Procedure:

5-Methylthiazolinone (9) (26.3 g) was suspended in 480 mL of anhydroustoluene. The solvent of this slurry was distilled at 44 C and 50 mbarreduced pressure to a total volume of 160 mL. To jacketed 3 L reactor,equipped with a Julabo LH-50 process chiller, N₂ line, thermocouple, andoverhead stirrer, was charged 110.2 g of chiral amine (2) solid. Thereactor and contents were flushed with N2. Toluene (375 mL) was chargedto the purged reactor via cannula, yielding a clear solution of chiralamine (2). This solution was cooled to −15° C. Butyllithium (3) (181 mL,2.7 M in toluene) was transferred via cannula to a 250 mL additionfunnel attached to the reactor. The butyllithium was added dropwise overa period of 45 minutes, with the Tint never rising above −8.0° C. TMEDA(4) (37 mL) was charged to the reactor via syringe after the Tint hadbeen re-established at −16.5° C. After a 20 minute aging, the 160 mLslurry of thiazalinone (9) in toluene was charged portionwise viacannula, with the Tint never rising above −13° C. The Tint was thenadjusted to 16° C. and the reaction was held for 30 minutes. After thisaging period, the Tint was readjusted to −16.5° C. I-propyl iodide (10)(90 mL) was charged via cannula over a period of 20 minutes, maintaininga Tint below −14° C. The Tint stabilized at −14.5° C. after completionof iPrI addition, and was stirred out for 16 hours.

After 16 hours, HPLC analysis indicated less than 3% residual startingmaterial and a de of 85.8%. The reactor was equipped with a 250 mLaddition funnel, to which was added 250 mL sat NH₄Cl. A fast dropwiseaddition of NH₄Cl was established and the saturated solution was addedover a period of 1.5 hours, during which time the Tint never rose above−7.0° C. After completion of the quench, the reactor contents werewarmed to 22° C., and the mixture was agitated. The stirring was thenhalted and the layers were allowed to separate for 5 minutes, afterwhich the bottom aqueous component was drained off. A second 250 mL sat.NH₄Cl quench was performed in the manner previously mentioned. Thetoluene layer was then acidified with 3×200 mL 2N AcOH and theextraction performed by agitation, phase separation, and draining of thebottom aqueous layer. A final extraction was performed with 200 mL ofsat. NaHCO₃ by the method previously outlined. The toluene layer postworkup was then polish filtered, yielding 630 mL of a clear solution.

This toluene layer was concentrated under reduced pressure (50 C and 60mbar) to a total volume of 90 mL. Octane (90 mL) was charged, and themurky mixture was concentrated to 50 mL total volume under theaforementioned conditions. This cycle of octane dilution to the mixture(90 mL each cycle) was performed until the ratio of octane to toluenewas 4:1 by ¹H NMR. The mixture was heated to 65 C (clear solution), andslowly cooled to 35 C, at which point seed (50 mg) was suspended in thecloudy solution. The resulting slurry was cooled to 22° C. over a periodof 2 hours and held 13 hours stirring under N2. Two additional 100 mLportions of octane were charged individually via an addition funnel, andafter 2.5 hours of vigorous stirring the slurry was filtered. The solidswere dried 16 hours with house vacuum under an N₂ sweep. A light brownsolid was obtained (9.8 g, 54.1% yield), LCAP 99%, de of 89.1%. ¹H NMR[(CD₃)₂SO] δ: 9.61 (d, 1H), 7.32 (comp m, 5H), 5.19 (m, 1H), 1.95 (m,1H), 1.50-1.45 (comp m, 6H), 0.95-0.56 (comp m, 6H). Note: a minorisomer was also visible by ¹H NMR.

Example 4 Preparation of(S)-5-methyl-2-((S)-1-phenylethylamino)-5-propylthiazol-4(5H)-one (12)

Materials MW Amount mMol Eq Other 5-Methylthiazolinone (9) 233.31 26.3 g112.56 1 96.9% de Chiral amine (2) 448.64 110.2 g 245.6 2 68628-85-2n-BuLi (3) — 181 mL 488.7 4 2.7M toluene TMEDA (4) 116.21 37 mL 245.2 2d = 0.775 g/mL n-PrI (5) 169.99 88 mL 900.48 8 d = 1.742 g/mL Toluene —160 + 375 mL — — —

Procedure:

5-Methylthiazolinone (9) (26.3 g) was suspended in 500 mL of anhydroustoluene. The solvent of this light slurry was distilled at 44 C and 50mbar reduced pressure to a total volume of 160 mL. To jacketed 3 Lreactor, equipped with a Julabo LH-50 process chiller, N₂ line,thermocouple, and overhead stirrer, was charged 110.2 g of chiral amine(2) solid. The reactor and contents were flushed with N₂. Toluene (375mL) was charged to the purged reactor via cannula, yielding a clearsolution of chiral amine (2). This solution was cooled to −15° C.Butyllithium (3) (181 mL, 2.7 M in toluene) was transferred via cannulato a 250 mL addition funnel attached to the reactor. The butyllithium(3) was added dropwise over a period of 45 minutes, with the Tint neverrising above −11.5 C. TMEDA (4) (37 mL) was charged to the reactor viasyringe after the Tint had been re-established at −16.5 C. After a 10minute aging, the 160 mL slurry of thiazalinone (9) in toluene wascharged portionwise via cannula, with the Tint never rising above −8.5°C. The Tint was then adjusted to 16° C. and the reaction was held for 50minutes. After this aging period, the Tint was readjusted to −17.0 C.N-propyl iodide (5) (88 mL) was charged via cannula over a period of 20minutes, maintaining a Tint below −14 C. The Tint stabilized at −14.5°C. after completion of nPrI addition, and was stirred out for 16 hours.

After 16 hours, HPLC analysis indicated less than 0.5% residual startingmaterial and a de of 61.2%. The reactor was equipped with a 250 mLaddition funnel, to which was added 250 mL sat NH₄Cl. A fast dropwiseaddition of NH₄Cl was established and the saturated solution was addedover a period of 1.5 hours, during which time the Tint never rose above−3.1° C. After completion of the quench, the reactor contents werewarmed to 22° C., and the mixture was agitated. The stirring was thenhalted and the layers were allowed to separate for 5 minutes, afterwhich the bottom aqueous component was drained off. A second 250 mL sat.NH₄Cl quench was performed in the manner previously mentioned. Thetoluene layer was then acidified with 3×200 mL 2N AcOH and theextraction performed by agitation, phase separation, and draining of thebottom aqueous layer. A final extraction was performed with 200 mL ofsat. NaHCO₃ by the method previously outlined. The toluene layer postworkup was then polish filtered, yielding 750 mL of a clear solution.

This toluene layer was concentrated under reduced pressure (60° C. and80 mbar) to a total volume of 90 mL. Octane (90 mL) was charged, and themurky mixture was concentrated to 60 mL total volume under theaforementioned conditions. This cycle of octane dilution to the mixture(90 mL each cycle) was performed until the ratio of octane to toluenewas 2:1 by ¹H NMR. The toluene/octane solution (60 mL total volume) washeated to 70° C., achieving a clear solution. After achieving a Tint of53° C., 50 mg of seed were charged. The slurry was cooled to 33° C. overa period of 20 minutes then reheated to 70° C. over 35 minutes. Thismixture was then cooled to 43.5° C. over 2 hours, and octane (160 mL)was charged to the slurry in a fast dropwise addition over 30 minutes.The slurry was then cooled to 22° C. and held 16 hours stirring underN₂. The slurry was filtered and dried under house vacuum with an N₂sweep for 4 hours, yielding 12.5 g (64.8% yield) of light brown solids,98% LCAP, de=85.7%. ¹H NMR [(CD₃)₂SO] δ: 9.60 (d, 1H), 7.33 (comp m,5H), 5.19 (m, 1H), 1.68 (m, 2H), 1.46-1.43 (comp m, 7H), 1.06 (m, 1H),0.86 (comp m, 3H). Note: a minor isomer was also visible by ¹H NMR.

Example 5 Preparation of(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-methyl-5-propylthiazol-4(5H)-one(6) of high diastereomeric excess

Materials MW Amount mMol Eq Other 5-Me/nPr Thiazalinone (6) 266.4 20.3 g76.0 1 n/a 5-Me/nPr Thiazalinone MSA salt (13) 362.51 10.6 g 29.2 1 n/aMethanesulfonic Acid (14) 96.11 5.2 mL 80.0 1.05 d = 1.481 g/mL IPA —100 mL — — 5X DCM — 100 mL — — 10X NaOH aq — 50 mL 50.0 1.75 1M

Procedure:

To a 250 mL 1 neck round bottom flask was suspended 20.4 g of crude5-Me/nPr thiazalinone (6) in 100 mL dry isopropanol at 22° C. To thisslurry was added methanesulfonic acid (14) (5.2 mL, 1.05 eq), which uponcomplete addition fully dissolved the solids yielding a homogeneoussolution. Heated over a period of 25 minutes to 50 C, held for 1 hour,then cooled to 22° C. and held 16 hours under N2. After this period thestill homogeneous solution was transferred to a 500 mL 3 neck roundbottom flask fitted with an overhead stirrer and a 500 mL additionfunnel. Heptane (285 mL) was added portion wise, after which the 22° C.mixture was cooled in an ice bath. After 10 minutes (Tint=8.2 C) 100 mgof seed in a 12× slurry in heptane was added. The mixture was held for16 hours and allowed to slowly warm to 22° C., resulting in a thickwhite slurry. This was filtered and dried (house vacuum/N₂ sweep) for 5hours to yield 10.6 g of the MSA salt (13), 95.1% de, mother liquorde=−42.7%. ¹H NMR [(CD₃)₂SO] δ: ¹H NMR [(CD₃)₂SO] δ: 9.36 (d, 1H), 3.75(m, 1H), 2.34 (s, 3H), 2.24 (m, 1H), 2.20 (m, 1H), 1.68 (m, 3H), 1.47(comp m, 8H), 1.12 (m, 4H), and 0.84 ppm (m, 3H). Note: a minor isomerwas also visible by ¹H NMR.

To a 250 Erlenmeyer flask was added 10.6 g of the 5-Me/nPr thiazalinoneMSA salt (13). This solid was subsequently dissolved with 100 mL dryDCM, yielding a clear 10× solution. NaOH (1N, 50 mL) was charged to thissolution and stirred vigorously for 20 minutes. After halting agitationthe biphasic system was transferred to a 250 mL separatory funnel, andthe upper aqueous layer was removed. Three water washes (75 mL each)were performed on the organic layer, the pH of the final water layerbeing 6.5-7.0. The DCM layer was polish filtered into a 250 mL roundbottom flask (100 mL total), and concentrated down to 20 mL total volume(40° C., 60 mbar). Isopropanol (100 mL) was charged to this solution andthe total volume was concentrated to 20 mL. An additional 20 mL of IPAwas charged to the flask to obtain a 3.75× solution of the free base inIPA. Upon cooling this mixture from the evaporator bath temp of 40 C, awhite solid precipitated. This was filtered and dried to yield 5.0 g ofthe product, 64.7% recovery, 99.4% LCAP and 95.9% de. ¹H NMR [(CD₃)₂SO]δ: 9.00 (d, 1H), 3.75 (m, 1H), 2.24 (m, 1H), 2.10 (m, 1H), 1.68 (m, 3H),1.47 (comp m, 8H), 1.12 (m, 4H), and 0.84 ppm (m, 3H).

Example 6 Preparation of(5S)-2-(bicyclo[2.2.1]hept-5-en-2-ylamino)-5-methyl-5-propylthiazol-4(5H)-oneof high diastereomeric excess

Materials MW Amount mMol Eq Other 5-Me/nPr Thiazalinone (8) 264.39 21.2g 80.2 1 n/a 5-Me/nPr Thiazalinone MSA salt (15) 360.49 17.5 g 49.0 1n/a Methanesulfonic Acid (14) 96.11 5.5 mL 84.2 1.05 d = 1.481 g/mL IPA— 100 mL — — 5X DCM — 175 mL — — 10X NaOH aq — 88 mL 88.0 2.00 1M

Procedure:

To a 250 mL 1 neck round bottom flask was suspended 20.4 g of crude5-Me/nPr thiazalinone (8) in 100 mL dry isopropanol at 22° C. To thisthick, pearl white slurry was added methanesulfonic acid (14) (5.5 mL,1.05 eq), which upon complete addition fully dissolved the solidsyielding a homogeneous solution. The mixture was heated over a period of15 minutes to 50° C., held for 35 minutes, then cooled to 22° C. andheld 16 hours under N₂. After this period the still homogeneous solutionwas transferred to a 1 L 3 neck round bottom flask fitted with anoverhead stirrer and a 500 mL addition funnel. Heptane (268 mL, 2× withrespect 134 mL total IPA solution) was added portion wise over 15minutes, after which the 22° C. mixture was cooled in an ice bath. After50 minutes the mixture was warmed to 22° C., and the thick white slurrywas aged for 16 hours. This was filtered and dried (house vacuum/N2sweep) for 5 hours, affording 17.5 g of the MSA salt (15) 73.0% yield,99.1% purity, 82.2% de. ¹H NMR [(CD₃)₂SO] δ: 9.40 (d, 1H), 6.21 (m, 1H),6.09 (m, 1H), 3.74 (m, 1H), 2.87 (m, 1H), 2.81 (m, 1H), 2.31 (s, 3H),1.54 (comp m, 10H), 1.04 (m, 1H), and 0.86 ppm (m, 3H).

To a 500 Erlenmeyer flask was added 17.5 g of the 5-Me/nPr thiazalinoneMSA salt (15). This solid was subsequently suspended in 175 mL of dryDCM to afford a slurry. Sodium hydroxide (1 M, 88 mL) was charged to theslurry and the biphasic mixture was stirred vigorously for 16 hours.After this period the biphasic mixture was transferred to a 1 Lseparatory funnel, allowing 5 minutes for phase separation. The basicaqueous layer was drained away from the organic phase, after which 3×130mL H₂O washes were performed on the DCM layer. The pH of the finalaqueous was 7.0. The DCM layer was polished filtered and concentrated to20 mL total volume. IPA (3.75×, 65 mL total) was charged and the entiremixture was concentrated to 20 mL total volume (40° C., 60 mbar). Anadditional 105 mL of IPA was charged and this solution was concentratedto 65 mL total volume (3.75×IPA). This mixture was then heated to 70°C., and then slowly cooled to 0 C. When the Tint was 66° C. water (52mL) was charged portion-wise over a period of 5 minutes. When Tint=30.0C a white slurry was achieved. This white slurry was stirred at 22° C.for 16 hours under N₂. After this period the slurry was cooled at 0° C.,filtered, and washed with 70 mL of 60:40 H₂O:IPA solution. The solidswere dried on a medium porosity frit for 4 hours under an N₂ sweep,affording 9.4 g (73% recovery) of a white solid, 89% LCAP, 93.1% de. ¹HNMR [(CD₃)₂SO] δ: 9.26 (d, 1H), 6.21 (m, 1H), 6.09 (m, 1H), 3.75 (m,1H), 2.86 (s, 114), 2.80 (s, 1H), 1.54 (comp m, 10H), 1.04 (m, 1H), and0.86 ppm (m, 3H). Note: a minor isomer was also visible by ¹H NMR.

Example 7 Preparation of(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one(19) of high diastereomeric excess

Step 1:

A 20 L reactor was assembled as described in the “Equipment” section(above) and placed under a nitrogen sweep. (S)-exo-2-norbornylthiourea(16) (801.4 g) was charged to the reactor followed by 3.0 L of absoluteethanol. Agitation was initiated (142 RPM) and this was followed byaddition of 2-bromopropionic acid (17) (509 mL) via graduated cylinder.The graduated cylinder was rinsed with 400 mL of absolute ethanol andthe rinse was transferred to the reactor. Sodium acetate (965.7 g) wasthen charged and this was followed by a final charge of 1.4 L ofabsolute ethanol. The reaction mixture was heated to 80° C. and aged atthis temperature for 3 hours, after which it was cooled to 22° C.Deionized water (13 L) was added and a small exotherm resulted. Themixture was allowed to return to 22° C. and aged for 12 h. The resultingsuspension was filtered through a medium-porosity sintered glass funnel.NOTE: At this stage, crude material was combined during filtration withcrude product from a parallel reaction with 234 g of thiourea. This wasnecessary due to the capacity limit of the 20 L reactor.

The solid remaining in the reactor was rinsed into the funnel withdeionized water (2 L) and the filter cake was washed with 1 L ofdeionized water. The solid was air-dried on the filter for 3 hours, thentransferred to drying trays and dried at 50° C. and 15 torr until TGAanalysis indicated water content of less than 3.0%. The dry weight wasrecorded (1311 g) and the solid was transferred to a clean 20 L jacketedreactor. MTBE (5.9 L) was added and agitation was initiated (120 RPM).The slurry was heated to 50° C. and aged at this temperature for 2 h.The mixture was then cooled to 22° C. and filtered through amedium-porosity sintered glass funnel. The collected solid was washedtwice with MTBE (500 mL each wash) and air-dried on the funnel for 1 h.The material was transferred to drying trays and dried at 50° C. and 15torr until TGA analysis registered water content of less than 1.0%. Thedried solid was packaged (isolated 1240 g, 91% yield, >98 A %).

Step 2: Asymmetric alkylation

A 20 L reactor was placed under a nitrogen sweep. (R,R)-chiral amine (2)(1761.2 g) was charged to the reactor. This was followed by a nitrogensweep for 15 minutes. Anhydrous toluene (6.0 L) was then charged andagitation was initiated. The reaction mixture was allowed to stir undera nitrogen sweep for an additional 15 minutes, after which the reactionmixture was cooled to −5° C. A 3 L dropping funnel was charged withn-BuLi (3) solution (2.9 L). Once an internal temperature of −5° C. hadbeen achieved, dropwise addition of the n-BuLi was initiated, ensuringthat internal temperature did not rise above 0° C. The reaction mixturewas cooled to −15° C. and aged for 30 minutes. TMEDA (4) (592 mL) wasthen added via cannula. 5-methylthiazolinone (18) (400 g) was slurriedin anhydrous toluene (1.6 L) in a separate 5 L, 3-neck round-bottomflask under a nitrogen sweep for 15 min. The resulting slurry wascharged portionwise to the reactor via cannula, adjusting addition rateand jacket temperature so as to maintain the internal temperature below0° C. The round-bottom flask used to prepare the substrate slurry wasrinsed with toluene (2×450 mL) and the washes were charged to thereactor. The reaction mixture was warmed to 22° C. and aged at thistemperature for 30 min. The mixture was then re-cooled to −15° C.Isopropyl iodide (10) (1.42 L) was charged via cannula at such a rate asto maintain temperature below −12.5° C., adjusting the jackettemperature as needed to control the resulting exotherm. An analyticalsample was pulled 20 min following completion of the isopropyl iodideaddition (following the sample preparation protocol in the analyticalsection).

The reaction mixture was allowed to age at −15° C. until >93% conversionwas obtained, and then quenched by dropwise addition of saturated NH₄Clsolution, again adjusting addition rate and jacket temperature tocontrol the resulting exotherm. The reaction mixture was warmed to roomtemperature and agitation was halted. Phases were allowed to separate(at least 20 min) and the lower aqueous layer was drained. 3.0 L ofsaturated NH₄Cl solution was added and the mixture agitated for 20minutes. The Phases were allowed to separate and the lower aqueous layerwas drained. Acetic acid solution (2 M, 3.3 L) was charged to thereactor, and the mixture agitated for 20 minutes. The phases wereallowed to separate and the lower aqueous layer was drained. This aceticacid wash was repeated.

Brine (3.3 L) was charged to the reactor, and the mixture was agitatedfor 20 minutes. The phases were allowed to separate and the loweraqueous phase was drained. Saturated NaHCO₃ solution (3.3 L) was chargedto the reactor slowly while agitating for 20 minutes. The phases wereallowed to separate (at least 20 min) and the lower aqueous phase wasdrained. A second NaHCO₃ (3.3 L) was performed and the lower aqueous wasdrained. Brine (3.3 L) was again charged to the reactor, the mixture wasagitated for 20 minutes. The phases were allowed to separate and thelower aqueous phase was drained.

A 200 mL sample of the crude toluene solution was reduced via vacuumdistillation to a final volume of 30 mL. The resulting suspension wasthen maintained at a temperature of 60° C. To the suspension was added100 mL of heptane while maintaining the temperature above 55° C. Oncethe addition of heptane was completed, the suspension was cooled to 5°C. over an hour period. The batch was held at 5° C. for 90 minutes. Thesolid was then filtered through a medium fritted glass filter and thecake was washed with a minimum amount (15 mL) of cold heptane (5° C.).The solid was dried in a vacuum oven at 55° C. for 16 hours. Isolated5.25 g of solid (67.7% yield).

Step 3 (MSA Salting)

A 3-neck, 2 L round bottom flask was placed under a N₂ sweep. Crudealkylation product (19) (84% de; 225 g) was then charged, followed byisopropyl alcohol (1125 mL, 5 volumes). Agitation was established andmethanesulfonic acid (14) (57.5 mL) was then charged via additionfunnel. The reaction mixture was heated to 50° C. and aged for 1 hour.The reactor contents were then cooled to 18-25° C. and aged for 1.5hours. The solid was then isolated by filtration with a Buchner funnel.An additional portion of isopropyl alcohol (338 mL, 1.5 volumes) wasused to rinse any remaining solid material from the 2 L round bottomflask. The wet cake was allowed to dry on the funnel for at least 1hour. The solid material was then transferred to a drying tray andplaced in a vacuum oven at 50° C. for 16 hours. Obtained 272.2 g (88.9%uncorrected yield, 95.98% de) of dry compound (20).

Step 4 (Free Basing)

To a 40 g suspension of MSA salt (20) in DCM (10×, 400 mL) in a 1000 mL,3 neck round bottom flask, equipped with a mechanical stirrer and anitrogen inlet, was added 5× of 1N NaOH (200 mL). The mixture wasstirred for 1 hour and transferred to a separatory funnel. The layerswere allowed to settle for 15 minutes and then split. The organic layerwas then washed with 5 volumes of DI water until the pH of the aqueouslayer was neutral. The organic layer (DCM) is filtered through a mediumfritted glass filter prior to proceeding with the solvent exchange.

An atmospheric distillation was performed in order to reduce the volumeof DCM to a level of 3.75× (150 mL). At this point, IPA (3.75×; 150 mL)was introduced into the flask and the atmospheric distillation wasresumed until the volume of the batch reached once again 3.75× (150 mL).An additional 3.75× (150 mL) IPA was introduced to the flask anddistillation was continued until the final volume of the batch was 3.75×(150 mL). The batch temperature during this stage was equivalent to theboiling point of IPA (−82° C.). To the hot solution (75±5° C.) ofproduct in IPA was added water (3×; 120 mL) at such a rate that thetemperature is maintained above 70° C. The mixture was cooled to 5° C.over a >1 hour period and held for 75 minutes. The solids were filtered,and washed with a minimum amount (−2×) of cold (5° C.) IPA/water mixture(40/60). The solid was dried in a vacuum oven at 55° C. for 17 hours.Isolated 27.97 g of product (19) (95.1% uncorrected yield; 99.76% de).

Example 8 Preparation of(5S)-2-(bicyclo[2.2.1]hept-5-en-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one(23) of high diastereomeric excess Step 1

A 20 L reactor was placed under a nitrogen sweep.(S)-exo-2-norbornenylthiourea (21) (587 g) was charged to the reactorfollowed by 2.97 L of absolute ethanol. Agitation was initiated, andthis was followed by addition of 2-bromopropionic acid (17) (377 mL) viaa graduated cylinder. Sodium acetate (715 g) was then charged. Thereaction mixture was heated to 80° C. and aged at this temperature for 4hours, after which it was cooled to 22° C. Deionized water (9 L) wasadded and a small exotherm resulted. The mixture was allowed to returnto 22° C. and aged for 12 h. The resulting suspension was filteredthrough a medium-porosity sintered glass funnel. The solid remaining inthe reactor was rinsed into the funnel with deionized water (1.5 L) andthe filter cake was washed with 0.5 L of deionized water. The solid wasair-dried on the filter for 3 hours, then transferred to drying traysand dried at 50° C. and 3-30 ton until TGA analysis indicated watercontent of less than 3.0%. The dry weight was recorded (728.9 g, 94%yield).

Step 2: Asymmetric alkylation

A 20 L reactor was placed under a nitrogen sweep as stated. (R,R)-chiralamine (2) amine (1610 g) was charged to the reactor. This was followedby a nitrogen sweep for 50 minutes. Anhydrous toluene (5.42 L) was thencharged and agitation was initiated. The reaction mixture was allowed tostir under a nitrogen sweep for an additional 10 minutes, after whichthe reaction mixture was cooled to −7.5° C. over 45 minutes. Thedropping funnel was charged with n-BuLi (3) solution (2.66 L), anddropwise addition of the n-BuLi was initiated. During this addition, theaddition rate and jacket temperature were adjusted to ensure thatinternal temperature did not rise above 0° C. Once the addition wascomplete, the dropping funnel was rinsed with anhydrous toluene (100 mL)transferred via cannula from a sure-seal bottle of toluene. The reactionmixture was cooled to −15° C., and TMEDA (4) (540 mL) was then added viacannula. 5-methylthiazolinone (22) (361.6 g) was slurried in anhydroustoluene (1.45 L) in a separate 5 L, 3-neck round-bottom flask under anitrogen sweep for 30 minutes. The resulting shiny was charged portionwise to the reactor via cannula, adjusting addition rate and jackettemperature so as to maintain the internal temperature below 0° C. Theround-bottom flask used to prepare the substrate slurry was rinsed withtoluene (2×468 mL) and the washes were charged to the reactor

The reaction mixture was warmed to 15° C. over 1.5 hours, and aged atthis temperature for 30 min (with chiller set at 22° C., max temp=20°C.). The mixture was then re-cooled to −15° C. over one hour.2-Iodopropane (10) (1.3 L) was charged via cannula at such a rate as tomaintain temperature below −12.5° C., adjusting the jacket temperatureas needed to control the resulting exotherm.

The reaction mixture was allowed to age at −15° C. until >93% conversionwas obtained, and then quenched by dropwise addition of saturated NH₄Clsolution (3.62 L), again adjusting addition rate and jacket temperatureto control the resulting exotherm. The reaction mixture was warmed toroom temperature and agitation was halted. Phases were allowed toseparate and the lower aqueous layer was drained. 4.82 L of saturatedNH₄Cl solution was added and the mixture agitated for 20 minutes. Thephases were allowed to separate and the lower aqueous layer was drained.Acetic acid solution (2 M, 3 L) was charged to the reactor, and themixture agitated for 30 minutes. The phases were allowed to separate andthe lower aqueous layer was drained. This acetic acid wash was repeated.Saturated NaHCO₃ solution (3 L) was charged to the reactor slowly whileagitating for 20 minutes. The phases were allowed to separate (at least20 min). The lower aqueous phase was drained. Water (3 L) was charged tothe reactor slowly while agitating for 20 minutes. The phases wereallowed to separate and the lower aqueous phase was drained.

The toluene layer was solvent-swapped into octane, with the final ratioof solvents ˜20:1, octane:toluene. The distillation was performed withthe internal temperature within the range of 19° C.-54° C., and thepressure within the range of 40-275 torr. After the desired solventratio was reached, with a final volume of 3.9 L, the slurry was filteredthrough a medium-porosity sintered glass funnel, rinsing with twoportions of octane (1400 mL total). The solids were dried on the filterfor 1-1.5 hours, and then transferred to a drying dish and dried in avacuum oven at 45-55° C., 3-30 ton for 18-42 hours. Obtained 370 g of awhite solid, 86% yield, 80.5% de.

Step 3 (MSA Salting)

A 5 L reactor was placed under a N₂ (g) atmosphere. Alkylation product(23) (80.5% de; 303.3 g) was then charged, followed by isopropyl alcohol(1820 mL, 6 volumes). Agitation was established and methanesulfonic acid(14) (78.2 mL) was then charged via addition funnel. The reactionmixture was heated to 50° C. and aged for 1 hour. The reactor contentswere then cooled to 20-24° C. and aged for 1.5 hours. The solid was thenisolated by filtration through a 2 L medium-porosity sintered glassfunnel. Two additional portions of isopropyl alcohol (2×303 mL, 2volumes total) were used to rinse any remaining solid material from the5 L reactor. The wetcake was allowed to dry on the funnel for at least 1hour. The solid material was then transferred to a drying tray andplaced in a vacuum oven at 50° C., 3-30 ton for 16 hours. Obtained 367.4g (88.9% uncorrected yield, 96.8% de) of dry compound.

The isolated solid (367.4 g) was recharged to the reactor followed byisopropyl alcohol (1886 mL). Agitation was established and the reactorcontents were heated to 50° C. over 105 minutes. The mixture was aged atthis temperature for 23 hours. It was then cooled to 20-24° C. over 2hours and aged for an additional 3 hours. The solid was isolated byfiltration through an 8 L medium-porosity sintered glass funnel. Anadditional portion of isopropyl alcohol (2×269 mL) was used to rinse thewet cake. The solid material was allowed to dry on the funnel for atleast 1 hour. It was then transferred to a drying tray and placed in avacuum oven at 50° C. for 16 hours. Obtained 357.2 g (97.2% yield, 99.3%de) of dry compound.

Step 4 (Free Basing)

A 20 L reactor was placed under a nitrogen sweep. The reactor wascharged with methanesulfonic acid salt (24) (598.6 g), and 5.73 L ofdichloromethane. Agitation was initiated and 2.86 L of 1N sodiumhydroxide was added to the suspension over 10 minutes, which caused arise in temperature from 18.1° C. to 21.6° C. This mixture was agitatedfor one hour then stopped, and the layers were allowed to settle. Thelower organic layer was drained. The upper aqueous layer was thendrained (pH=14). The organic layer was returned to the reactor for waterwashes. The reactor was charged with 2.86 L of DI water and the biphasicmixture was stirred for 15 minutes. Agitation was then stopped and thelayers were allowed to settle. The lower organic layer was drained. Theupper aqueous layer was then drained (pH=10). The water wash wasrepeated once, resulting in a pH of 7. The final organic layer wasfiltered through a medium porosity sintered glass funnel and returned toa clean 20 L reactor equipped with a distillation apparatus.

A vacuum distillation was performed in order to reduce the volume from7.8 L to 4.0 L (6.7×). The range in temperature was 11° C. to 40° C.,and the range in pressure was 80-180 torr. When a volume of 4.0 L wasreached, 4.0 L of IPA was added and the vacuum distillation repeateduntil a volume of 3.0 L (6.8 volumes) was reached, and DCM levels wereundetectable. At this point, the solution was warmed to 60° C. over 2hours, and then 2420 L of DI water were added over 10 minutes, resultingin an 8° C. temperature decrease. The chiller was then ramped to 35° C.,and when the internal temperature reached 41° C., an additional 580 mLDI water was added (total water=6.8 volumes, IPA: Water=1:1). Over onehour the temperature of the solution was ramped down to 0° C.-3° C., andthen the solution was filtered through a 8 L M porosity sintered glassfunnel. The solids were rinsed with 880 mL (2×) of a 70:30 water:IPAmixture. The resulting material was transferred to a drying tray andplaced in a vacuum oven at 50° C., 3-30 torr for 16 hours. Obtained392.3 g (89.3% yield, 99.3% de) of a white solid (23).

Example 9 Preparation of lithium(R)-propane-1,3-diylbis(((R)-1-phenyl-2-(piperidin-1-yl)ethyl)amide)(25)

Other chiral bases described herein may be prepared readily byprocedures that are analogous to the method shown in scheme above.

Example 10 One-pot Alkylation Reaction to Make(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one

A 3-neck 250 mL round-bottom flask equipped with an overhead stirrer andthermocouple was charged with 5-methylthiazolinone (2 g, 8.92 mmol, 1equiv)

and amine (8.8 g, 19.6 mmol, 2.2 equiv)

One neck was capped with a septum, and a needle inserted which wasconnected to a nitrogen and vacuum source. The flask was evacuated andback-filled with nitrogen. Toluene (40 mL, 20 volumes, AldrichSure-Seal) was charged via syringe to the flask. Agitation wasinitiated, and a needle was inserted in the septum under a positivepressure of nitrogen to purge the atmosphere. TMEDA (2.96 mL, 19.6 mmol,2.2 equiv) was added via syringe, and the atmosphere was purged for 5min. The solution was cooled to −15° C. (+/−5° C.), and the n-BuLi (2.6M in toluene) (15.1 mL, 39.2 mmol, 4.4 equiv) was added via syringe over35 minutes. The temperature did not exceed −15° C. (+/−5° C.). Thereaction pot was warmed to 22° C. (+/−3° C.) over 30 min and then heldfor 90 min. At this point, the reaction was cooled to 0° C. (+/−3° C.)and 2-iodopropane (7.14 mL, 71.4 mmol, 8.0 equiv) was added over 15 min.A small latent exotherm of ˜4° C. was observed. The reaction was allowedto warm to 22° C. over 1-2 h, and then held at 22° C. for an additional16 h. The reaction was quenched with saturated aqueous ammonium chloride(16 mL, 8 volumes) by adding it drop-wise via syringe over 30 min. Thereaction mixture was added to a separatory funnel, and the two layerswere separated. The upper organics layer was found to contain 1.86 g,78% assay yield (uncorrected) of(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-onewith a stereo selectivity of 87:13 and 110 mg, 5.5% of startingmaterial. This reaction stream can be worked-up in the same manner as atwo-pot alkylation reaction.

Example 11 One-Pot Asymmetric Alkylation Using (+)-Ephedrine HCl

A. Using 2.5 M n-Butyllithium in Hexanes

A 5 L reactor equipped with an overhead stirrer and a 5-port lid whichwas connected to an addition funnel, a nitrogen inlet, and athermocouple was charged with 5-methylthiazolinone (95.5 g, 0.426 mol,1.0 equiv)

and (1S,2R)-(+)-ephedrine HCl (103.1 g, 0.511 mol, 1.2 equiv)

The reactor was purged with nitrogen for 45 min. by blowing nitrogeninto the inlet adapter and then out through an attached outlet adapter.Me-THF (573 mL, 493 g, 6 volumes) was added via cannula, and the reactorwas purged for an additional 30 min. The nitrogen outlet adapter wasremoved so that the reactor was under a blanket of nitrogen, and thenthe reactor was cooled to −15° C. (+/−3° C.). 2.5 M n-butyllithium inhexanes (0.815 L, 2.04 mol, 4.8 equiv) was charged to an addition funnelvia cannula. The chiller attached to the reactor was set to −30° C., andthe butyllithium was added to the reactor drop-wise over 2 h such thatthe internal temperature did not exceed −9° C. After the addition wascomplete, the reactor was warmed to 22° C. (+/−3° C.) over 1 h and heldat this temperature for 30 min. At this point, the addition of2-iodopropane (341 mL, 3.41 mol, 8.0 equiv) portion-wise from an inertround-bottom flask was begun. 10 minutes into the addition, the chillerwas set to 10° C. in order to absorb a small exotherm which brought thetemperature to 26° C. The entire addition took 25 min., and the chillerwas re-set to 22° C. This reaction mixture stirred at 22° C. for 16 h,and analysis of an aliquot by HPLC revealed >99% conversion and 77:23dr. The chiller was set to 10° C., and sulfuric acid (1.05 M, 907 mL,9.5 volumes) was added drop-wise via an addition funnel over 45 min. Thechiller was re-set to 22° C., and this mixture was stirred for 1 h.Dichloromethane (478 mL, 5 volumes) and water (287 mL, 3 volumes) wereadded and stirred 10 min. After separation, the lower aqueous layer (1.4Kg) was drained, analyzed by HPLC, and found to contain 45 g ofephedrine (53%). Sodium bisulfate monohydrate (20 w/v %, 907 mL, 9.5volumes) was added to the reactor and the two layers were agitated for30 min. The lower aqueous layer (1 Kg) was drained, analyzed by HPLC,and found to contain 19 g (23%) of ephedrine.

The organics, (2.2 Kg) were drained, analyzed by HPLC, and found tocontain the desired(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one(101 g, 89%, 77:23 dr) and (+)-ephedrine (2.9 g, 3%). An additionalsodium bisulfate monohydrate (20 w/v %, 907 mL, 9.5 volumes) wash can beincorporated here, if needed, to remove excess ephedrine. The organicswere returned to the reactor and washed with sodium bicarbonate (sat.aq.) (907 mL, 9.5 volumes), the layers drained, and the organicssubjected to salting and freebasing in a manner analogous to steps 3 and4 of Example 7 above to isolate the product.

B. Using 6.6 M n-Hexyllithium in Hexanes

A 100 mL round-bottom flask equipped with a thermocouple was chargedwith 5-methylthiazolinone (5 g, 22.3 mmol, 1.0 equiv)

and (1S,2R)-(+)-ephedrine HCl (5.4 g, 26.7 mmol, 1.2 equiv). A septumwas added to seal the flask, and it was then evacuated and backfilledwith nitrogen (g). Me-THF (30 mL, 6 volumes) was added via syringe, andthe flask was cooled to −15° C. (+/−3° C.). n-hexyllithium in hexanes(6.6 M, 16.2 mL, 107 mmol, 4.8 equiv) was added drop-wise to the flaskvia syringe over 20 min. so that the internal temperature did not exceed−15° C. (+/−3° C.). The flask was warmed to 22° C. (+/−3° C.) over 30minutes and held at that temperature for 45 min. 2-iodopropane (17.8 mL,178 mmol, 8.0 equiv) was added to the flask at 22° C. (+/−3° C.) over 5min., and a small latent exotherm to 26° C. was observed. This reactionmixture stirred at 22° C. (+1-3° C.) for 16 h, and then sulfuric acid(1.05 M, 47 mL, 9.5 volumes) was added drop-wise to the reaction mixtureover 90 min. The internal temperature did not exceed 26° C. during thisaddition. Dichloromethane (15 mL, 3 volumes) and water (10 mL, 2volumes) were added to the reaction mixture and stirred to dissolveprecipitate. The layers were transferred to a separatory funnel and thelower aqueous layer (70 g) was drained, analyzed by HPLC, and found tocontain ephedrine (3.5 g, 80%). The organic layer was washed with sodiumbisulfate monohydrate (20 w/v %, 47 mL, 9.5 volumes) and the layers wereallowed to separate. The lower aqueous layer (56 g) was drained,analyzed by HPLC, and found to contain ephedrine (800 mg, 18%) and(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-oneand its racemate (28 mg, 0.5%).

The organic layer (89 g) was drained, analyzed by HPLC, and found tocontain(5S)-2-(bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one(5.1 g, 85%, 76:24 dr). An additional sodium bisulfate monohydrate (20w/v %, 47 mL, 9.5 volumes) wash can be incorporated here, if needed, toremove excess ephedrine. The organics were returned to the separatoryfunnel and washed with sodium bicarbonate (sat. aq.) (47 mL, 9.5volumes). The two layers were slow to separate, and additional brine (3volumes) was added to aid the separation. Finally, the layers separatedand were drained.

We claim:
 1. A process for the preparation of a compound of formula I,or a tautomer, stereoisomer, optical isomer, prodrug, orpharmaceutically acceptable salt thereof:

comprising (a) contacting a compound of formula II

with a chiral base selected from the group consisting of:

in the presence of a deprotonating reagent and alkylating agent R³-LG;wherein: Z is S or O; R¹ is selected from C₁₋₈ alkyl, C₂₋₈ alkenyl,C₃₋₁₀-cycloalkyl, C₃₋₁₀-cycloalkenyl, C₃₋₁₀-cycloalkyl-C₁₋₈-alkyl,C₃₋₁₀-cycloalkenyl-C₁₋₈-alkyl, aryl, aryl-C₁₋₈-alkyl, heterocyclyl,heterocyclyl-C₁₋₈-alkyl and haloalkyl; wherein any aryl, cycloalkyl, orheterocyclyl residue is optionally independently substituted by one ormore C₁₋₈-alkyl, aryl, halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl,R⁴R⁵N—C₁-C₈-alkyl, C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl orC₁-C₈-alkyl-sulfonyl; R² and R³ are independently selected fromC₁₋₈-alkyl, C₁₋₈-alkoxy, C₃₋₁₀-cycloalkyl, heterocyclyl,C₃₋₁₀-cycloalkyl-C₁₋₈-alkyl, CN—C₁₋₈-alkyl, aryl, aryl-C₁₋₈-alkyl,heterocyclyl-C₁₋₈-alkyl and haloalkyl; wherein any aryl, cycloalkyl, orheterocyclyl residue is optionally independently substituted by one ormore C₁₋₈-alkyl, aryl, halogen, halo-C₁-C₈-alkyl, HO—C₁-C₈-alkyl,R⁴R⁵N—C₁-C₈-alkyl, C₁-C₈-alkyl-OR⁶, —OR⁶, (C₃-C₁₀)-cycloalkyl orC₁-C₈-alkyl-sulfonyl; R⁴ and R⁵ are each independently selected fromhydrogen, C₁-C₈ alkyl, C₁-C₈ alkoxy, —NR⁶R⁶, —S—(C₁-C₈)alkyl, aryl andheterocyclyl; where in the definition of R⁴ and R⁵ any alkyl, alkoxy,heterocyclyl or aryl may be substituted with one to three substituentsselected from -halo, unsubstituted C₁-C₈ alkyl, unsubstituted C₁-C₈alkoxy, unsubstituted C₁-C₈ thioalkoxy and unsubstitutedaryl(C₁-C₄)alkyl R⁶ is independently selected from hydrogen, C₁-C₈alkyl, aryl-C₁-C₈ alkyl, C₁-C₈ alkoxy, —S—(C₁-C₈)alkyl, heterocyclyl andaryl; where in the definition of R⁶ any alkyl, heterocyclyl or aryl maybe substituted with one to three substituents selected from -halo,unsubstituted C₁-C₈ alkyl, unsubstituted C₁-C₈ alkoxy, unsubstitutedC₁-C₈ thioalkoxy and unsubstituted aryl(C₁-C₄)alkyl LG is a leavinggroup.
 2. The process according to claim 1, further comprising the stepsof (b) contacting the product of (a) with an acid HB to form a salt offormula I′

wherein B is an organic or inorganic anion; and (c) reacting the salt offormula I′ with a base to form the compound of formula I.
 3. The processaccording to claim 1, wherein Z is S.
 4. The process according to claim1, wherein R₁ is selected from the group consisting of


5. The process according to claim 4, wherein R₁ is


6. The process according to claim 1, wherein, R₂ and R₃ areindependently selected from methyl, isopropyl, and propyl.
 7. Theprocess according to claim 6, wherein R₂ is methyl and R₃ is isopropyl.8. The process according to claim 7, wherein the chiral base is


9. The process according to claim 1, wherein the de of the compound offormula I is at least 85%.
 10. The process according to claim 1, whereinthe leaving group LG is selected from the group consisting of Cl, Br, I,—OS(O)₂CH₃, —OS(O)₂C₄F₉, —OS(O)₂CF₃, and —OS(O)₂(4-CH₃-phenyl).
 11. Aprocess for the preparation of a compound according to formula III:

comprising (a) contacting a compound of formula (IV)

 with a chiral base selected from the group consisting of:

 or an acid addition salt thereof in the presence of a deprotonatingreagent and; (b) reacting the product of step (a) with isopropyl iodide.12. The process according to claim 11, wherein the chiral base is

or an acid addition salt thereof.